本文实例讲述了php实现的支持imagemagick及gd库两种处理的缩略图生成类及其用法实例，非常具有实用价值。分享给大家供大家参考。具体如下：

一、功能:

1.按比例缩小/放大

2.填充背景色

3.按区域裁剪

4.添加水印，包括水印的位置，透明度等

使用imagemagick/GD库实现，imagemagick地址：www.imagemagick.org

需要安装imagemagick，安装方法如下：http://www.jb51.net/article/55528.htm

二、实现方法：

PicThumb.class.php类文件如下：

<?php /** 缩略图生成类,支持imagemagick及gd库两种处理 * Date: 2013-07-15 * Author: fdipzone * Ver: 1.2 * * Func: * public set_config: 设置参数 * public create_thumb: 生成缩略图 * private fit: 缩略图片 * private crop: 裁剪图片 * private gd_fit: GD库缩略图片 * private gd_crop: GD库裁剪图片 * private get_size: 获取要转换的size * private get_crop_offset: 获取裁图的偏移量 * private add_watermark: 添加水印 * private check_handler: 判断处理程序是否已安装 * private create_dirs: 创建目录 * private exists: 判断参数是否存在 * private to_log: 记录log * private hex2rgb: hex颜色转rgb颜色 * private get_file_ext: 获取图片类型 * * ver: 1.1 增加GD库处理 * ver: 1.2 增加width,height错误参数处理 * 增加当图片colorspace不为RGB时作转RGB处理 * 修正使用crop保存为gif时出现透明无效区域问题，使用+repage参数，删除透明无效区域即可 * * tips:建议使用imagemagick * GD库不支持透明度水印,如果必须使用透明水印,请将水印图片做成有透明度。 * GD库输出gif如加透明水印，会有问题。 */ class PicThumb{ // class start private $_log = null; // log file private $_handler = null; // 进行图片处理的程序,imagemagick/gd库 private $_type = 'fit'; // fit or crop private $_source = null; // 原图路径 private $_dest = null; // 缩略图路径 private $_watermark = null; // 水印图片 private $_opacity = 75; // 水印圖片透明度,gd库不支持 private $_gravity = 'SouthEast'; // 水印摆放位置 NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast private $_geometry = '+10+10'; // 水印定位,gd库不支持 private $_croppos = 'TL'; // 截图的位置 TL TM TR ML MM MR BL BM BR private $_bgcolor = null; // 填充的背景色 private $_quality = 90; // 生成的图片质量 private $_width = null; // 指定区域宽度 private $_height = null; // 指定区域高度 // 初始化 public function __construct($logfile=''){ if($logfile!=''){ $this->_log = $logfile; } } // 设置参数 public function set_config($param=array()){ $this->_handler = $this->exists($param, 'handler')? strtolower($param['handler']) : null; $this->_type = $this->exists($param, 'type')? strtolower($param['type']) : 'fit'; $this->_watermark = $this->exists($param, 'watermark')? $param['watermark'] : null; $this->_opacity = $this->exists($param, 'opacity')? $param['opacity'] : 75; $this->_gravity = $this->exists($param, 'gravity')? $param['gravity'] : 'SouthEast'; $this->_geometry = $this->exists($param, 'geometry')? $param['geometry'] : '+10+10'; $this->_croppos = $this->exists($param, 'croppos')? $param['croppos'] : 'TL'; $this->_bgcolor = $this->exists($param, 'bgcolor')? $param['bgcolor'] : null; $this->_quality = $this->exists($param, 'quality')? $param['quality'] : 90; $this->_width = $this->exists($param, 'width')? $param['width'] : null; $this->_height = $this->exists($param, 'height')? $param['height'] : null; } /** 创建缩略图 * @param String $source 原图 * @param String $dest 目标图 * @return boolean */ public function create_thumb($source, $dest){ // 检查使用的handler是否已安装 if(!$this->check_handler()){ $this->to_log('handler not installed'); return false; } // 判断区域宽高是否正确 if(!is_numeric($this->_width) || !is_numeric($this->_height) || $this->_width<=0 || $this->_height<=0){ $this->to_log('width or height invalid'); return false; } // 判断源文件是否存在 if(!file_exists($source)){ $this->to_log($source.' not exists'); return false; } // 创建目标文件路径 if(!$this->create_dirs($dest)){ $this->to_log(dirname($dest).' create fail'); return false; } $this->_source = $source; // 源文件 $this->_dest = $dest; // 目标文件 // 处理图片 switch($this->_type){ case 'fit': if($this->_handler=='imagemagick'){ return $this->fit(); }else{ return $this->gd_fit(); } break; case 'crop': if($this->_handler=='imagemagick'){ return $this->crop(); }else{ return $this->gd_crop(); } break; default: $this->to_log($this->_type.' not fit and crop'); return false; } } /** 按比例压缩或拉伸图片 * @return boolean */ private function fit(){ // 判断是否填充背景 $bgcolor = ($this->_bgcolor!=null)? sprintf(" -background '%s' -gravity center -extent '%sx%s' ", $this->_bgcolor, $this->_width, $this->_height) : ""; // 判断是否要转为RGB $source_info = getimagesize($this->_source); $colorspace = (!isset($source_info['channels']) || $source_info['channels']!=3)? ' -colorspace RGB ' : ''; // 命令行 $cmd = sprintf("convert -resize '%sx%s' '%s' %s -quality %s %s '%s'", $this->_width, $this->_height, $this->_source, $bgcolor, $this->_quality, $colorspace, $this->_dest); // 记录执行的命令 $this->to_log($cmd); // 执行命令 exec($cmd); // 添加水印 $this->add_watermark($this->_dest); return is_file($this->_dest)? true : false; } /** 裁剪图片 * @return boolean */ private function crop(){ // 获取生成的图片尺寸 list($pic_w, $pic_h) = $this->get_size(); // 获取截图的偏移量 list($offset_w, $offset_h) = $this->get_crop_offset($pic_w, $pic_h); // 判断是否要转为RGB $source_info = getimagesize($this->_source); $colorspace = (!isset($source_info['channels']) || $source_info['channels']!=3)? ' -colorspace RGB ' : ''; // 命令行 $cmd = sprintf("convert -resize '%sx%s' '%s' -quality %s %s -crop %sx%s+%s+%s +repage '%s'", $pic_w, $pic_h, $this->_source, $this->_quality, $colorspace, $this->_width, $this->_height, $offset_w, $offset_h, $this->_dest); // 记录执行的命令 $this->to_log($cmd); // 执行命令 exec($cmd); // 添加水印 $this->add_watermark($this->_dest); return is_file($this->_dest)? true : false; } /** GD库按比例压缩或拉伸图片 * @return boolean */ private function gd_fit(){ // 获取生成的图片尺寸 list($pic_w, $pic_h) = $this->get_size(); list($owidth, $oheight, $otype) = getimagesize($this->_source); switch($otype){ case 1: $source_img = imagecreatefromgif($this->_source); break; case 2: $source_img = imagecreatefromjpeg($this->_source); break; case 3: $source_img = imagecreatefrompng($this->_source); break; default: return false; } // 按比例缩略/拉伸图片 $new_img = imagecreatetruecolor($pic_w, $pic_h); imagecopyresampled($new_img, $source_img, 0, 0, 0, 0, $pic_w, $pic_h, $owidth, $oheight); // 判断是否填充背景 if($this->_bgcolor!=null){ $bg_img = imagecreatetruecolor($this->_width, $this->_height); $rgb = $this->hex2rgb($this->_bgcolor); $bgcolor =imagecolorallocate($bg_img, $rgb['r'], $rgb['g'], $rgb['b']); imagefill($bg_img, 0, 0, $bgcolor); imagecopy($bg_img, $new_img, (int)(($this->_width-$pic_w)/2), (int)(($this->_height-$pic_h)/2), 0, 0, $pic_w, $pic_h); $new_img = $bg_img; } // 获取目标图片的类型 $dest_ext = $this->get_file_ext($this->_dest); // 生成图片 switch($dest_ext){ case 1: imagegif($new_img, $this->_dest, $this->_quality); break; case 2: imagejpeg($new_img, $this->_dest, $this->_quality); break; case 3: imagepng($new_img, $this->_dest, (int)(($this->_quality-1)/10)); break; } if(isset($source_img)){ imagedestroy($source_img); } if(isset($new_img)){ imagedestroy($new_img); } // 添加水印 $this->add_watermark($this->_dest); return is_file($this->_dest)? true : false; } /** GD库裁剪图片 * @return boolean */ private function gd_crop(){ // 获取生成的图片尺寸 list($pic_w, $pic_h) = $this->get_size(); // 获取截图的偏移量 list($offset_w, $offset_h) = $this->get_crop_offset($pic_w, $pic_h); list($owidth, $oheight, $otype) = getimagesize($this->_source); switch($otype){ case 1: $source_img = imagecreatefromgif($this->_source); break; case 2: $source_img = imagecreatefromjpeg($this->_source); break; case 3: $source_img = imagecreatefrompng($this->_source); break; default: return false; } // 按比例缩略/拉伸图片 $tmp_img = imagecreatetruecolor($pic_w, $pic_h); imagecopyresampled($tmp_img, $source_img, 0, 0, 0, 0, $pic_w, $pic_h, $owidth, $oheight); // 裁剪图片 $new_img = imagecreatetruecolor($this->_width, $this->_height); imagecopyresampled($new_img, $tmp_img, 0, 0, $offset_w, $offset_h, $this->_width, $this->_height, $this->_width, $this->_height); // 获取目标图片的类型 $dest_ext = $this->get_file_ext($this->_dest); // 生成图片 switch($dest_ext){ case 1: imagegif($new_img, $this->_dest, $this->_quality); break; case 2: imagejpeg($new_img, $this->_dest, $this->_quality); break; case 3: imagepng($new_img, $this->_dest, (int)(($this->_quality-1)/10)); break; } if(isset($source_img)){ imagedestroy($source_img); } if(isset($tmp_img)){ imagedestroy($tmp_img); } if(isset($new_img)){ imagedestroy($new_img); } // 添加水印 $this->add_watermark($this->_dest); return is_file($this->_dest)? true : false; } /** 获取目标图生成的size * @return Array $width, $height */ private function get_size(){ list($owidth, $oheight) = getimagesize($this->_source); $width = (int)($this->_width); $height = (int)($this->_height); switch($this->_type){ case 'fit': $pic_w = $width; $pic_h = (int)($pic_w*$oheight/$owidth); if($pic_h>$height){ $pic_h = $height; $pic_w = (int)($pic_h*$owidth/$oheight); } break; case 'crop': if($owidth>$oheight){ $pic_h = $height; $pic_w = (int)($pic_h*$owidth/$oheight); }else{ $pic_w = $width; $pic_h = (int)($pic_w*$oheight/$owidth); } break; } return array($pic_w, $pic_h); } /** 获取截图的偏移量 * @param int $pic_w 图宽度 * @param int $pic_h 图高度 * @return Array $offset_w, $offset_h */ private function get_crop_offset($pic_w, $pic_h){ $offset_w = 0; $offset_h = 0; switch(strtoupper($this->_croppos)){ case 'TL': $offset_w = 0; $offset_h = 0; break; case 'TM': $offset_w = (int)(($pic_w-$this->_width)/2); $offset_h = 0; break; case 'TR': $offset_w = (int)($pic_w-$this->_width); $offset_h = 0; break; case 'ML': $offset_w = 0; $offset_h = (int)(($pic_h-$this->_height)/2); break; case 'MM': $offset_w = (int)(($pic_w-$this->_width)/2); $offset_h = (int)(($pic_h-$this->_height)/2); break; case 'MR': $offset_w = (int)($pic_w-$this->_width); $offset_h = (int)(($pic_h-$this->_height)/2); break; case 'BL': $offset_w = 0; $offset_h = (int)($pic_h-$this->_height); break; case 'BM': $offset_w = (int)(($pic_w-$this->_width)/2); $offset_h = (int)($pic_h-$this->_height); break; case 'BR': $offset_w = (int)($pic_w-$this->_width); $offset_h = (int)($pic_h-$this->_height); break; } return array($offset_w, $offset_h); } /** 添加水印 * @param String $dest 图片路径 */ private function add_watermark($dest){ if($this->_watermark!=null && file_exists($this->_watermark) && file_exists($dest)){ list($owidth, $oheight, $otype) = getimagesize($dest); list($w, $h, $wtype) = getimagesize($this->_watermark); // 水印图比原图要小才加水印 if($w<=$owidth && $h<=$oheight){ if($this->_handler=='imagemagick'){ // imagemagick 添加水印 $cmd = sprintf("composite -gravity %s -geometry %s -dissolve %s '%s' %s %s", $this->_gravity, $this->_geometry, $this->_opacity, $this->_watermark, $dest, $dest); $this->to_log($cmd); exec($cmd); }else{ // gd 添加水印 switch($wtype){ case 1: $water_img = imagecreatefromgif($this->_watermark); break; case 2: $water_img = imagecreatefromjpeg($this->_watermark); break; case 3: $water_img = imagecreatefrompng($this->_watermark); break; default: return false; } switch($otype){ case 1: $dest_img = imagecreatefromgif($dest); break; case 2: $dest_img = imagecreatefromjpeg($dest); break; case 3: $dest_img = imagecreatefrompng($dest); break; default: return false; } // 水印位置 switch(strtolower($this->_gravity)){ case 'northwest': $posX = 0; $posY = 0; break; case 'north': $posX = ($owidth - $w) / 2; $posY = 0; break; case 'northeast': $posX = $owidth - $w; $posY = 0; break; case 'west': $posX = 0; $posY = ($oheight - $h) / 2; break; case 'center': $posX = ($owidth - $w) / 2; $posY = ($oheight - $h) / 2; break; case 'east': $posX = $owidth - $w; $posY = ($oheight - $h) / 2; break; case 'southwest': $posX = 0; $posY = $oheight - $h; break; case 'south': $posX = ($owidth - $w) / 2; $posY = $oheight - $h; break; case 'southeast': $posX = $owidth - $w; $posY = $oheight - $h; break; } imagealphablending($dest_img, true); imagecopy($dest_img, $water_img, $posX, $posY, 0, 0, $w, $h); switch($otype){ case 1:imagegif($dest_img, $dest, $this->_quality); break; case 2:imagejpeg($dest_img, $dest, $this->_quality); break; case 3:imagepng($dest_img, $dest, (int)(($this->_quality-1)/10)); break; } if(isset($water_img)){ imagedestroy($water_img); } if(isset($dest_img)){ imagedestroy($dest_img); } } } } } /** 判断处理程序是否已安装 * @return boolean */ private function check_handler(){ $handler = $this->_handler; if(!in_array($handler, array('imagemagick', 'gd', null))){ return false; } // 检查是否有安装imagemagick $imagemagick_installed = strstr(shell_exec('convert -version'),'Version: ImageMagick')!=''? true : false; // 检查是否有安装gd库 $gd_installed = function_exists('gd_info')? true : false; switch($handler){ case 'imagemagick': return $imagemagick_installed; break; case 'gd': return $gd_installed; break; case null: if($imagemagick_installed){ $this->_handler = 'imagemagick'; return true; } if($gd_installed){ $this->_handler = 'gd'; return true; } break; } return false; } /** 创建图片目录 * @param String $path * @return boolean */ private function create_dirs($dest){ if(!is_dir(dirname($dest))){ return mkdir(dirname($dest), 0777, true); } return true; } /** 判断参数是否存在 * @param Array $obj 数组对象 * @param String $key 要查找的key * @return boolean */ private function exists($obj,$key=''){ if($key==''){ return isset($obj) && !empty($obj); }else{ $keys = explode('.',$key); for($i=0,$max=count($keys); $i<$max; $i++){ if(isset($obj[$keys[$i]])){ $obj = $obj[$keys[$i]]; }else{ return false; } } return isset($obj) && !empty($obj); } } /** 记录log * @param String $msg 要记录的log讯息 */ private function to_log($msg){ if($this->_log){ $msg = '['.date('Y-m-d H:i:s').']'.$msg."rn"; file_put_contents($this->_log, $msg, FILE_APPEND); } } /** hex颜色转rgb颜色 * @param String $color hex颜色 * @return Array */ private function hex2rgb($hexcolor){ $color = str_replace('#', '', $hexcolor); if (strlen($color) > 3) { $rgb = array( 'r' => hexdec(substr($color, 0, 2)), 'g' => hexdec(substr($color, 2, 2)), 'b' => hexdec(substr($color, 4, 2)) ); } else { $r = substr($color, 0, 1) . substr($color, 0, 1); $g = substr($color, 1, 1) . substr($color, 1, 1); $b = substr($color, 2, 1) . substr($color, 2, 1); $rgb = array( 'r' => hexdec($r), 'g' => hexdec($g), 'b' => hexdec($b) ); } return $rgb; } /** 获取图片类型 * @param String $file 图片路径 * @return int */ private function get_file_ext($file){ $filename = basename($file); list($name, $ext)= explode('.', $filename); $ext_type = 0; switch(strtolower($ext)){ case 'jpg': case 'jpeg': $ext_type = 2; break; case 'gif': $ext_type = 1; break; case 'png': $ext_type = 3; break; } return $ext_type; } } // class end ?>

demo示例代码如下：

<?php define('ROOT', dirname(__FILE__)); require(ROOT."/PicThumb.class.php"); $logfile = ROOT.'/PicThumb.log'; $source1 = ROOT.'/pic/source.jpg'; $dest1 = ROOT.'/pic/1.jpg'; $dest2 = ROOT.'/pic/2.gif'; $dest3 = ROOT.'/pic/3.png'; $source2 = ROOT.'/pic/source_cmyk.jpg'; $dest4 = ROOT.'/pic/4.jpg'; $dest5 = ROOT.'/pic/5.gif'; $dest6 = ROOT.'/pic/6.png'; $watermark = ROOT.'/pic/watermark.png'; // 按比例生成缩略图 $param = array( 'type' => 'fit', 'width' => 100, 'height' => 100, ); $obj = new PicThumb($logfile); $obj->set_config($param); $flag = $obj->create_thumb($source1, $dest1); if($flag){ echo '<img src="pic/'.basename($dest1).'">'; }else{ echo 'create thumb fail'; } // 按比例生成缩略图,不足部分用#FF0000填充 $param = array( 'type' => 'fit', 'width' => 100, 'height' => 100, 'bgcolor' => '#FFFF00' ); $obj = new PicThumb($logfile); $obj->set_config($param); $flag = $obj->create_thumb($source1, $dest2); if($flag){ echo '<img src="pic/'.basename($dest2).'">'; }else{ echo 'create thumb fail'; } // 裁剪250x250的缩略图,裁剪位置是底部中间,水印位置西南,透明度50 $param = array( 'type' => 'crop', 'croppos' => 'BM', 'width' => 250, 'height' => 250, 'watermark' => $watermark, 'opacity' => 50, 'gravity' => 'SouthWest' ); $obj = new PicThumb($logfile); $obj->set_config($param); $flag = $obj->create_thumb($source1, $dest3); if($flag){ echo '<img src="pic/'.basename($dest3).'">'; }else{ echo 'create thumb fail'; } // 按比例生成缩略图 CMYK格式 $param = array( 'type' => 'fit', 'width' => 100, 'height' => 100, ); $obj = new PicThumb($logfile); $obj->set_config($param); $flag = $obj->create_thumb($source2, $dest4); if($flag){ echo '<img src="pic/'.basename($dest4).'">'; }else{ echo 'create thumb fail'; } // 按比例生成缩略图,不足部分用#FF0000填充 CMYK格式 $param = array( 'type' => 'fit', 'width' => 100, 'height' => 100, 'bgcolor' => '#FFFF00' ); $obj = new PicThumb($logfile); $obj->set_config($param); $flag = $obj->create_thumb($source2, $dest5); if($flag){ echo '<img src="pic/'.basename($dest5).'">'; }else{ echo 'create thumb fail'; } // 裁剪250x250的缩略图,裁剪位置是底部中间,水印位置西南,透明度50 CMYK格式 $param = array( 'type' => 'crop', 'croppos' => 'BM', 'width' => 250, 'height' => 250, 'watermark' => $watermark, 'opacity' => 50, 'gravity' => 'SouthWest' ); $obj = new PicThumb($logfile); $obj->set_config($param); $flag = $obj->create_thumb($source2, $dest6); if($flag){ echo '<img src="pic/'.basename($dest6).'">'; }else{ echo 'create thumb fail'; } ?>

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希望本文所述对大家的PHP程序设计有所帮助